Vault-light



O. H. BASQUIN. V LLLLLLLL T.

No. 586,214. Patented July 13, 1897.

(No Model.) 2 Sheets-811813132 O.H,B A SQU1N.

VAULT LIGHT.

Patented July 13,1897.

UNITED STATES PATENT OFFICE.

OLIN II. BASQUIN, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGN-MENTS, TO TI-IE LUXFER PRISM PATENTS COMPANY, OF TEST VIRGINIA.

VAU LT-LIG HT.

SPECIFICATION forming part of Letters Patent N o. 586,214, dated July13, 1897.

Application filed January 23,1897. Serial No. 620,458. (No model.)

To cl/ZZ whom, it may concern:

Beit known that I, OLIN I-I. BAsQUIN, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois,

have invented certain new and useful Improvements in Vault-Lights, ofwhich the following is a specication.

My invention relates to vault-lights for diffusing and distributing thelight, and has for ro its object to provide the new and improvedprism-lights for this purpose illustrated in the accompanying drawings,wherein- Figure l is a section through a lens or vaultlight embodying myinvention. Fig. 2 is a section through a modified form of my device.Fig. 3 is a section through a further modified form of my device. Fig.il. is a section through a pavement composed of my prism-lights.

Like letters refer to like parts throughout zo the several ngures.

The object of my invention is to form a prism-light which will throw thelight as near to the edge of the prism next in advance as practicableand still allow it to pass by the 2 5 prisms without being obstructedthereby, thus avoiding the loss of light ordinarily occurring. I havefound that the prism-light herein illustrated approaches this result asnear as it is practicable to do so. The several construcgoitions hereinshown all approximate this result.

Referring now to Eig. l, which shows a body portion A, provided with theprojecting parts or prisms B, I have found that if thereflecting-surface C is curved in a manner similar to that shown-thatis, if it is a convex curvethe rays of light falling on thereceiving-surface D and passing through the prism will be reflected bythat surface and subsequently be 4o by the other prism-surface retractedso as to clear the prism next adjoining, as shown, the rays of light,after leaving the prism, being thrown in as nearly horizontal lines asis practicable. The curve given to this surface deponds, of course, uponthe several conditions, and I therefore do not wish to limit myself toany particular curve, the only limitation being that it shall be curvedso as, in conjunction with the other surface of the prism,

5o whether that be curved or not, to converge, substantially all thelight falling upon the receiving-surface associated with said prism on aline just below the lower line of the next preceding prism.

Referring now to Fig. 2, Ihave shown a construction for obtaining thesame result when the reflecting-surface C is straight. Iii-this case therefracting-surface E is curved, such surface being given a convex curve,as shown.

In Fig. 3 I have shown a construction where- 6o in two curved surfacesare used, the reflecting-surface C and the refracting-surface E bothbeing curved. In this construction both curves act to change thedirection of the rays of light, so as to make them leave the prisms inas nearly horizontal lines as is practicable and still lhave them passbelow the adjoining prism or lens.

I do not of course presume to have shown in these drawings all thepossible forms by 7o which the result sought can be attained, and indeedI have designed other forms than those shown. The ideal device along thelines of my invention would be one in which all of the rays of lightentering are received 7 5 and directed forwardly, so as to most nearlyapproach without impinging upon the prism in front. Cf course this wouldbe most desirable in such lights as are called vaultlights.7 8o

Referring to Eig. i, Gis the vault beneath the pavement; H, theretaining-wall; J, a column support-ing the building; K, astorefront,and the pavement-light is composed, as indicated, of a set of my prisms.

' I have described my improvement as being a body of glass with a seriesof prisms. Of course my invention is realized in a body of glass with asingle prism, or in a body of glass with a series of prisms, or in astruc- 9o ture made up of bodies of glass having one or more prisms,provided that the relation of the prisms to the body of the glass issuch as to bring about the result which I have described. 9 5

To determine the character and relations of the two faces of the prism Iproceed as follows: Knowing the direction from which the light is to bereceived and the direction of the receiving-surface, I arbitrarilydeterroo mine the width of the prism and place on a diagram upon whichthe line indicating the direction from which the light is to come andthe line indicating the direction of the surface of the prism have beenplaced two dots in a line parallel to the direction of thereceiving-surface an d separated from each other by a distance equal tothe arbitrarily determined width of the prism. In the case of thisinvention the object is to throw all of the light received from thepredetermined direction upon the receiving-surface opposite a givenprism, forward and as nearly as possible upon the line just below thenext preceding prism. I therefore may lay off a line indicating onesurface of such prism arbitrarily. I draw lines to indicate a largenumber of rays of light both entering and leaving the prism, thoseleaving` the prism being converged upon the line immediately below thenext preceding prism and those entering the prism being parallel to thedetermined direction. The undetermined face of the prism may nowobviously be determined by laying down a number of short lines acrossthese rays, which short lines are so positioned that the rays fallingupon each are turned in the direction of the rays leaving such line, andby connecting these short surfaces in the proper manner to form acontinuous surface the previously undetermined surface of the prism isestablished, and all the rays received upon the receiving-surface fromthe predetermined direction will by such a prism so formed be convergedupon the line j ust below the next preceding prism, and will neitherstrike such preceding prism nor be directed appreciably below the same,and no two of such rays will be parallel to each other.

I have spoken of my invention as a vaultlight. It is more correctlydescribed, however, asa prism-tile,7 and I prefer to use that term.

I claiml. Avault-lightcomprisingareceiving-surface adapted to be placedin an approximately horizontal plane, one or more projecting ribs orprisms on the opposite sides thereof, each prism having two convergingsurfaces, one for reflecting, the other for refracti ng the light, andone of. said surfaces curved in such manner that substantially all ofthe light falling upon the surface of the vault-light will passthereinto and be successively treated by the two surfaces of the prism,so that it is converged upon a line a little farther from thercceivingsurface than is the lower edge of such prism and in advance ofthe lower edge of such prism by a distance substantially equal to thegreatest width of such prism measured in the direction toward which thelight is to be thrown.

2. A vault-light comprising a recei\v'ing-sur face adapted to be placedin an approximately horizontal plane, one or more projecting ribs orprisms on the opposite sides thereof, each prism having two convergingsurfaces, one for reflecting, the other for refract-ing the light, andboth of said surfaces curved in such manner that substantially all ofthe light falling upon the surface of the vault-light will passthereinto and be successively treated by the two surfaces of the prismso that it is converged upon aline a little farther from thereceiving-surface than is the lower edge of such prism, and in advanceof the lower edge of such prism by a distance substantially equal to thegreatest width of such prism measured in the direction toward which thelight is to be thrown.

3. A prism-light comprising a substantially flatbody of glass with areceivin g-surfaee on one side, and one or more prisms on the otherside, said prisms forwardly projecting at their lower extremities andhaving two converging surfaces, one of which is curved, the lowerextremity of each of said prisms projecting in front of a line drawnthrough the forward upper extremity of said prism and substantiallyperpendicular to the receiving-surface, so that substantially all of thelight falling upon the surface of the vault-light will pass thereintoand be successively treated by the two surfaces of the prism so that itis converged upon a line a little farther from the receiving-surfacethan is the lower edge of such prism and in advance of the lower edge ofsuch prism by a distance substantially equal to the greatest width ofsuch prism measured in the direction toward which the light is to bethrown.

t. A vault-light comprisingareceiving-surface adapted to be )laced in anapproximately horizontal plane and provided with project.- ing ribs orprisms having each two conver ging surfaces, one for reflecting thelight received, and the other for refracting the reflected light, thereflecting surface being curved and the lower edge of such prism projecting forward of a line through the upper forward surface of suchprism and substantially perpendicular to the receiving-surface, and therefracting-surface of such prism substantially parallel to the directionfrom which the light to be treated is to be received, so thatsubstantially all of the li ght fallin g upon the surface of thevault-light vwill pass thereint-o and be successively treated by the twosurfaces of the prism so that it is converged upon a line a littlefarther from the receiving-surface than is the lower edge of such prismand in advance of the lower edge of such prism by a distancesubstantially equal to the greatest width of such prism measured in thedirection toward which the light is to be thrown.

OLIN ll. lASQUlN. lVitnesses:

DONALD M. (tritium, Fnaxcis W. PARKER.

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